Gas furnace



AprilA 6 1926.

.- C. W. DE FOREST GAS FURNACE -Filed May 22I 1922 l la 65.91. W. DJiQmJ/f the novelty of the invention therein duly Patented l Apr. 6, 1926.

f .In the drawings,

UNITED STATE y 1,579,599 PATENT OFFICE.

'ons rUaNAcn. f

i Application led May 22, 1922. 'Serial No. 562,679.

To all whom t may concern: v v

Be it known Athat I, CORNELIUS W. DE FOREST, a citizen of the United States, and a resident of Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Gas Furnaces, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this application.

My invention relates to gas furnaces for hot air generation, more particularly for heating buildings.

In fevices ordinarily employed for. heating of buildings by means of gas, there is a large waste in available heat through the iiues. One of the reasons for this is that a certain amount of ,flow of the products of combustion to the escape flue is necessary in order to insure a'gainst escape of the said products into the building being heated. Another of the reasons is that the furnaces are not so constructed that the incoming air is progressively heated b the products of combustion as said pro ucts are progressively cooled. With a -method of air heating by counter-flow of incoming and outgoing air and gases, as noted, the dow of the products of combustion need not be retarded so as to run danger of escape of fumes, and practically all available heat therein will be imparted to the incoming'air.

will in this specification endeavor to describe a structurel embodying the principle of progressive heating and cooling of flux air and elilux gases, it being understood that thisl is merely a preferred construction illustrative of my invention. Thus I accomplish .the objects of my invention above stated, by that certain'construction and arrangement of parts to be hereinafter more specifically pointed out and claimed. y

Figure 1 is a longitudinal vertical section of the device on the line 1--1 of Figure 2. Figure 2 is a vhorizontal section through the device taken O11 the line 2-2 of Fi re 1.

Referring to'\the illustrative embo iment of the drawings, the outer casing of the fur- .naceis shown as having a base 1 with the j sides and top of the casing forming a rec es' f shell portion2 tangular iat toppedA shell 2 and a some-I elongated shell 3. From the what tapering, I

the hot air pipes 4 extend upwardly as from the usual furnace dome. At the outer end ofthe shell `portion 3 the cold air to be 'heated is introduced,

.and a blower or fan 5 is located in this mouth or. outer end so as to set upa forced iiow of cold a1r,'when desired.

The gas burner sections and conduits are specially shaped and arranged to fit the shell of the type shown.

The cast casing 6, having radiating iins 7, is set in the shell portion 2 in such a way as to extend across it at right angles to the shell portion. The casing 6 extends across the shell 2 and lis rounded `at the top. The burners 8, 8, in the form of pipes with jets in them of desired pat-tern are inserted into the casing from one end and a grate servin to mount suitable tiles 9 for heat retention, may be disposed in the casing above the burners,

From the casing'6 a series of fairly closely interspacedpipes 10 extend to an intermedi` .ate heater casing 11, said casing 11' being a casting with radiating fins. Hot-flue vgas baiiies 12.mounted on cross rods 13 may be disposed in the casing as indicated in Figchimney, this casing 14 also extending across the shell portion 3,'and having radiating fins and bafflesfas in the case of the casing 11.

Extending from the casing 11 to the cas-i' ing 14 I preferabl arrange the conductor pipes in a series o upwardly curved pipes 16 and downwardlyv curved pipes 17, said ipes being fairly closely interspaced, and,

1f desired, 'staggered' relative to each other in thetwo series.

In connection withthe shell ortions 2A and 3 I provide a series of ba es for the area to be heated. These are arranged so as to cause the air to ass through the various piping systems and) flow around the three- .casings l Thusat the entrance an inclined baiile 18 is provided which extends clear across the shel 'portion 3 and begins approximately beneath the casing 14 and thence inclines upwardly until it reachesits greatest hei ht about at the center of the downwar y curved pipes 17, whence it inclines down againand terminates approximately at the inner end of the casing portion 6.

A small baille 19 is provided which extends across the shell portion 3 and contacts with the upwardly curved pipes 16 at vabout their highest points.

A battle 2O is provided which begins approximately above the casing 11 and thence inclines down until it contacts substantially with the pipes 1() at their middle point from whence the bafiie curvesl upwardly again and terminates at the top of the shell portion 2.

The last baHie 21 begins at thie top of the portion 2 opposite the baiiie 20 and thence curves outwardly from the shell Wall above the casing 6 and thence recedcs toward the shell portion 2 again.

Following the incoming air it will be noted that it is forced to travel around the casing 14, thence through the curved pipe assembly and around the casisg 11 and thence down and around the pipe assembly 10 and around the casing 6 and thence upwardly around the top of the casing 6 to 4 the conductor pipes 4.

The vgases are burned in thence How through the pipes 11 and thence through the pipes to the casing 14 and thence to the Hue.

The coldest air strikes the outgoing gases, so that a large difference of temperature is preserved at the incoming end between the product to be heated and the generated hot products. As the vincoming air becomes more heated, it is constantly striking hotter and hotter heat radiating elements, with the the casing 6, to the caslng vhottest point of contact just before the said alr gets to the conductor pipes.

I have found in a furnace constructed according to the drawings, that the flue gases in the last casing are reduced to such a low temperature that condensation of the steam in the gases takes place, thereby liberating much latent heat.

Where re-circulation of air is employed in heating rooms, the How of cold air through the furnace will not be so rapid, and as the heat radiating and batlie system tends to retard the How, it is desirable for best results to operate the fan.

The fan operation may be regulated by the user so that thevolume to keep the roomsy heated at desired temperature is sent through the conductor pipes.

I have found by exhaustive tests, however, that the blower may be automatically maintained. v

It will be recognized Without illustration that the user of the gas can determine what quantity of gas should be burnt at the burner jets to get the best effect in his building. Thus some housescan be best kept at proper temperature by a three-quarter-opening of the burners, which, operating together with of air necessary some accepted thermostat located in the rooms, will turn on and 0H' the gas when the rooms come above and below the correct temperature. I have indicatedva gas regulating valve control Aarm on the gas in- How pipe at D.

This leaves the furnace as a unit to operate as perfectly as possible, i. e., to impart to the incoming air the most heat possible from the burned gases. This is accomplished by keeping the Hue temperature .1t some figure below212 F. so that latent heat of condensation is used, and so that the best counterHow heating relation is maintained.

For this reason I can locate in the outlet Hue pipe 15 thermostat A and utilize this thermostat in the position indicated by the member illustrated in Figure 1 and marked to close the circuit C to the fan motor B Whenever the Hue temperature goes above some selected temperature, for example,

' the theoretical loss in greater ranges of temperature change in the rooms to be heated, taking into consideration valso the more recent increases in cost of fuel gas.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is l 1. In a furnace, a shell, hot air conductor pipes extending therefrom, a Hue, a combustion chamber within said shell, means for conducting the products of combustion through said shell to the Hue, means for introducing air to be heated into said shell, said shell, gas conducting means and air introduction meansbeing so arranged that the How of products of combustion and air are opposite to each other,'the incoming air being introduced to the shell beyond the Hue exit with the hottest conducting means being located closest to the hot air conductor pipes.

2. In a furnace, a shell, hot air conductor pipes extending therefrom, a Hue, a combustion" chamber within said shell, means for conducting the products of combustion through said shell to the Hue, means for introducin air to be heated into said shell, said shell, gas conducting means and air introduction means being so arranged that the How of products of combustion and air are opposite to each other, the incoming air being introduced to the shell beyond the Hue exit with the hottest conducting means being located closest to the hot air conductor pipes, and a means for controlling the How of incoming air.

introduction means being so arranged that' the flow of products of combustion and air areI opposite to each other, the incon'iing air being introduced to the shell beyond the liuc exit with the hottest conducting means of gases being located closest to the hot air conductor pipes, and a means for controlling the flow oll 'incoming air, said means being mtomatically operated thermostatieally from the flue temperature of. the outgoing products of combustion.

4. In a furnace, a shell, hot air conductor pipes extending therefrom, a flue, a combus tion chamber Within said shell, means for conducting the products of combustion through said shell to the flue, means for introducing air to be heated into said shell, said shell, gas conducting means and air introduction means being so arranged that the flow of products of combustion and air l are opposite to each other, the incoming air being introduced to the shell beyond the Hue exit with the hottest conducting means of gases being located closest to the hot air conductor pipes, and a blower for creating a forced draft of` incoming air, and means for thermostatically controlling the blower to preserve the outgoing temperature 0f the Products of combustion below condensation point. l v

5. Ina furnace and flue for burning gases and heating incoming air for conduction to a point to be heated, a thermostat for controlling the introduction of gas'and'a thermostat in the flue for controlling the introduction of air to be heated, and means for setting up a counterlow of incoming air and outgoing flue gases comprising a casing extending from the furnace to the flue with separate air and gas conduits in which incoming air and flue gases are adapted to flow in opposite directions therein to cut down flue temperatures. v

6. In a furnace, a shell having a hot air conductor pipe portion and an extension away-therefroni, a gas burner and easing in thc conductor pipe port ion, a series of interspaeed pipes extending therefrom through the shell extension to a terminal casing, said last named casing being in communication with a iiue, bailiing means arranged with relation'to the conductor pipes to cause ail. within the shell to fiow in contact with said inici-spaced pipes and a blower for introducing air into the shell beyond the terminal casino. i

7.'.ln a furnace, a shell, heat radiating means in the shell within which gases are burned and conducted to a flue, a flue, hot air conductor pipes, and means for introdiming air to be heated into the shell at the liuc portion thereof, and means for automatically controlling said air introduction to inamtain the fflue temperature below the condensation point.

CORNELIUS W. DE Fonns'r. 

